Tk_GetUid, Tk_Uid - convert from string to unique identifier

       char *string (in)                         String   for  which  the  corresponding  unique  identifier  is
                                                 desired.
________________________________________________________________________________________________________________

Tk_GetUid returns the unique identifier corresponding to string.  Unique identifiers are similar to atoms
       in Lisp, and are used in Tk to speed up comparisons and searches.  A unique identifier (type Tk_Uid) is a
       string pointer and may be used anywhere that a variable of type “char *” could be used.   However,  there
       is  guaranteed  to  be  exactly one unique identifier for any given string value.  If Tk_GetUid is called
       twice, once with string a and once with string b, and if a and b have the same string value (strcmp(a, b)
       == 0), then Tk_GetUid will  return  exactly  the  same  Tk_Uid  value  for  each  call  (Tk_GetUid(a)  ==
       Tk_GetUid(b)).  This means that variables of type Tk_Uid may be compared directly (x == y) without having
       to  call  strcmp.   In  addition,  the return value from Tk_GetUid will have the same string value as its
       argument (strcmp(Tk_GetUid(a), a) == 0).

       atom, unique identifier

Tk                                                                                                Tk_GetUid(3tk)

       Tk_GetUid, Tk_Uid - convert from string to unique identifier

#include<tk.h>

       Tk_Uid
       Tk_GetUid(string)